Prior art firearm housings include a longitudinal slit to receive a firing lever or a cocking slide which can be manually grasped and moved to load the weapon. Such longitudinal slits have appeared in many locations in prior art housings. For example, such longitudinal slits have been located just behind and/or bordering an ejection opening formed on the right side of the housing, on top of the housing in front of the breech, on the left long side of the housing, etc. The length of the longitudinal slit, if it does not grade into the ejection opening, is generally at least twice that of the cartridge. In many instances, the length of the slit is much longer than twice the length of the cartridge. This longitudinal slit is also often lengthened to the open rear end of the housing in order to permit assembly of the weapon. Such an approach is often used, for example, in instances where the firing lever is rigidly connected to the breech mechanism.
In addition to the ejection opening and the mentioned longitudinal slit, the housing also has other openings extending in the longitudinal direction of the housing. For example, prior art housings include an opening for receiving a magazine, and one or more opening(s) through which the trigger mechanism cooperates with the breech mechanism. The latter opening is also generally opened toward the rear end of the housing.
Box-like housings are advantageous in comparison with trough-like housings (for example, the housing used in the Russian Kalaschnikov M 74 automatic weapon). Trough-like housings are covered by a separate, non-supporting component. Box-like housings are advantageous over such trough-like housings in that the box-like housings remain sufficiently rigid even when their wall thickness is reduced. For this reason, for more than a half century (starting with the Sturmgewehr 44), sheet metal housings have mostly had the closed, box-like shape.
However, the rigidity of these box-like housings are severely compromised by the openings discussed above so that thin-walled sheet metal housings or plastic housings can only be used if the breech mechanism is directly locked with the barrel such that the housing is not used to transfer forces therebetween. Because of its great length, the aforementioned longitudinal slit makes a particularly significant contribution to reducing the rigidity of the housing.
In order to achieve good shooting results with each shot with limited design expenditure, a change has recently been made to adapt weapons so that they can be alternately used for right and left shooting with equal (particularly high) firing accuracy. In a weapon with a firing lever or cocking slide mounted on the side, the firing lever or cocking slide must be movable from one side of the housing to the other to facilitate manipulation thereof with the non-shooting hand of a user during loading. This arrangement, however, requires that two of the longitudinal slits mentioned above must be defined in the housing, one on each side for alternatively receiving the cocking slide. Since only one of these longitudinal slits will be in use at any given time, the unutilized slit can be optionally covered with a separate cover in order to avoid penetration of sand, dirt, and/or other debris into the housing. Moreover, especially in the so-called "bullpup" design in which the breech recoil extends to the rear end of the stock, two ejection openings are required since, during left sided shooting, the weapon must eject to the left and, during right sided shooting, the weapon must eject to the right.
From the foregoing it can be seen that the modifications to adapt a weapon to both left and right shooting result in a large number of openings in the housing. Among those openings, the longitudinal slits for the firing lever or cocking slide have a particularly adverse effect on the rigidity of the housing; especially when they are in communication with their corresponding ejection openings. Moreover, covering of the unused longitudinal slit is problematical. Each ejection opening can, however, be covered in the usual manner with a cover or cap, as is already used, for example, in the Sturmgewehr 44.
Prior art box-like housings generally do not include partitions or offsets in the region of the motion path of the firing lever or cocking slide. Offsets are avoided if possible, since they promote catching of the weapon by branches, and the like. Only the front wall of the magazine shaft could be viewed as a partition. In the region of the motion path, however, the outside of the housing is designed as smooth and continuous as possible.